# If $a, h, b$ are in A.P., then the triangular area formed by the pair of lines $ax^2 + 2hxy + by^2=0$ and the line $x-y=-2$ (in square units) is :
( A ) $\begin{vmatrix} \frac{(a-b)^2}{a+b} \end{vmatrix}$
( B ) $\begin{vmatrix} \frac{a^2+b^2}{a-b} \end{vmatrix}$
( C ) $\begin{vmatrix} \frac{a+b}{a-b} \end{vmatrix}$
( D ) $\begin{vmatrix} \frac{a^2+b^2}{a+b} \end{vmatrix}$